Nail shank broaching apparatus and method

ABSTRACT

A method of, and a device for broaching nail shanks. Pairs of nails having distended shank portions near their points are positioned between pairs of spaced apart broaching surfaces, which surfaces are then closed to contact the shanks above the distended portions. Then the surfaces are moved downwardly along the shanks to reshape the distended portions. The nails are moved into broaching position transversely of their axes, and are supported adjacent their heads against axial movement during the broaching operation.

United States Patent [191 Kobylanski 1 Feb. 27, 1973 NAIL SHANK BROACHING APPARATUS AND METHOD [75] Inventor: Anthony Kobylanski, Montreal,

Quebec, Canada [73] Assignee: Signode Corporation, Glenview, [IL

[22] Filed: Jan. 28, 1971 [21] Applv N0.: 110,508

[52] U.S. Cl. ..10/54, 10/18, 10/52, 90/24 E [51] Int. Cl ..B21g 3/14 [58] Field of Search ..10/18, 20, 31, 34, 35, 53, 10/54, 57, 59, 61, 63, 68, 81, 3, 4, 8, 9,10, 14, 19, 20.5, 21, 24, 27, 28, 37-39, 60, 69, 40, 54; 72/340, 341, 406, 407; 90/24 E; 29/481; 51/57-61, 53, 289, 290

[56] References Cited UNITED STATES PATENTS 3,621,176 11/1971 Valenti ..29/481 X 1,027,383 5/1912 Glover et a1..' ..10/18 2,737,013 3/1956 Gora ..90/24 E X 3,015,995 1/1962 Fahy ..90/24 E X FOREIGN PATENTS OR APPLICATIONS 403,500 10/1924 Germany ..10/63 65,621 10/1927 Austria ..10/39 Primary Examiner-Charles W. Lanham Assistant Examiner-E. M. Combs Attorney-Dressler, Goldsmith, Clement & Gordon [57] ABSTRACT A method of, and a device for br'oaching nail shanks. Pairs of nails having distended shank portions near their points are positioned between pairs of spaced apart broaching surfaces, which surfaces are then closed to contact the shanks above the distended portions. Then the surfaces are moved downwardly along the shanks to reshape the distended portions, The nails are moved into broaching position transversely of their axes, and are supported adjacent their heads against axial movement during the broaching operation. I

3 Claims, 8 Drawing Figures PATENTED FEBZY I913 3.717. 8 91 SHEET 1 0r 2 This invention relates to a nail broaching device and to a method of broaching the shanks of nails.

Nails, such as those having diamond-shaped points, are today made primarily by machines utilizing cutting tools or cutting dies in which portions of a wire or a wire blank are cut therefrom to form the nail point. Other methods have been suggested for forming points on nails, such as, for example, methods utilizing a combined compression and rolling operation.

Typical nail-forming machines for carrying out the most frequently utilized pointing methods, i.e., the cutting of pieces from wire stock to provide sharp pointed nails, are described, for example, in U.S. Pat. No. 3,362,035. Methods utilizing combined compression and rolling processes for the forming of points on nails are illustrated and described, such as in US. Pat. Nos. 2,917,756 and 1,632,703. A hybrid method of forming nails is illustrated in US. Pat. No. 423,017, wherein nail points are formed by a combined squeezing and cutting method.

In my copending application entitled Pointing Apparatus and Method, filed on Dec. 31, 1970 under Ser. No. 103,018, I describe a new method for pointing the free end of nails, and a machine for accomplishing that purpose. The use of that machine avoids the removal of pieces of wire which intrude into the sensitive parts of nail making machines, and provides a number of other substantial advantages.

When a nail blank is squeezed to form a point in the manner described in my copending application, frequently a portion of the shank of the nail blank immediately above the formed, pointed end becomes distended, i.e., it slightly increases in diameter. Although that distension or distortion is of no consequence in many environments in which such nails are used, where the nails formed are to be used in, and are to be driven as from nailing guns, such as pneumatic nailing guns, it is important that the shanks be quite straight and of uniform diameter throughout their lengths. As such, any distension or increase in the diameter of a nail shank resulting from a pointing operation should desirably be eliminated when the nail is to be so used.

In accordance with this invention, a broaching device specially designed to act upon the distended portions of elongate nail shanks, such as shanks of nails formed in accordance with my aforementioned copending application, is positioned to receive such nails, preferably in pairs and transversely of their longitudinal axes, and preferably immediately after they have been pointed. The broaching device comprises a pair. of broaching die members providing broaching surfaces adapted to be spaced apart so that they may receive a nail shank, and adapted to close to contact the shank above the affected, distended or enlarged portion. Thereafter, the broaching die members and the nail shank are moved relatively with respect to the axis of the shank from above the distended portion of the shank to the point of the nail, thereby to reshape the distended portion and to return the diameter and shape of the shank to the predetermined desired shape and diameter, normally that of the unaffected upper portion of the shank. Preferably the broaching surfaces are moved with respect to the shank while the shank itself is restrained against axial movement.

Further objects, advantages and features of this invention will become apparent from the following description and drawings of which:

FIG. 1 is a plan view of a broaching device of this invention;

FIG. 2 is a side elevational view of the broaching device of FIG. 1 taken substantially along the line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view of the broaching device of FIG. 1 taken substantially along the line 3-3 of FIG. 2;

FIG. 4 is a cross-sectional view of the broaching device of FIG. 1 taken substantially along the line 4-4 of FIG. 3, but in a more fully open position;

FIG. 5 is a cross-sectional view similar to FIG. 4 and illustrates the broaching device of FIG. 1 in another position;

FIG. 6 is a cross-sectional view of the broaching device of FIG. 1 taken substantially along the line 6-6 of FIG. 5;

FIG. 7 illustrates a nail which has been pointed, and with which the broaching device of this invention is adapted to be used; and

FIG. 8 is a further view of the nail of FIG. 7 after it has been broached in a broaching device of this invention.

A preferred embodiment of a broachin g device 10 of this invention is illustrated in FIGS. 1 to 6. Broaching device 10 includes a support assembly comprising a base plate 12 defining a central, generally rectilinear opening 14, a pair of generally U-shaped slide block holders 16 and a pair of stops 18. Slide block holders 16 are secured to base plate 12 by a plurality of screws 20 and stops 18 are similarly secured to base plate 12 by a suitable plurality of screws 22. Each of the slide block holders 16 mounts and vertically locates a slide block 24 via screws 26. Several screws 20 project through base plate 12 into slide blocks 24, thereby firmly to position and to stabilize blocks 24 on the support assembly. The support assembly is suitably secured to a main frame assembly (not shown) adjacent a nail support means.

The support assembly of broaching device 10 mounts broaching means positioned and adapted to operate on the shanks of nails presented thereto. The broaching means comprises a pair of broaching die members 30 positioned and supported on the base plate 12 to be moved vertically with respect to the base plate 12, and to be moved toward and away from each other between an open shank receiving position and a closed broaching position.

Each die member 30 comprises a die block 32, a pair of insert clamps 34, a pair of replaceable die inserts 36 providing broaching surfaces, and an insert retainer 38. Insert clamps 34 are secured to the die blocks 32 by screws 40. The pair of die inserts 36 (which are preferably of a carbide material) are restrained from movement longitudinally by an insert retainer 38 which is received in, and mates with complementary grooves in die inserts 36 and in die block 3.2. The die inserts 36 are restrained from vertical removal by the complementary tongue and groove configuration (see FIG. 3) of the confronting surfaces of the insert clamps 34 and die block 32. Each die insert 36 defines broaching surfaces comprising a vertically oriented semi-circular groove 42 proportioned to fit the shank of a nail, and to cooperate with the like groove 42 in a confronting insert 36. Preferably the lower edges of the grooves 42 are slightly outwardly flared thereby to prevent binding and to facilitate smooth movement along the nail shanks. Because each of the die blocks 32 mounts a pair of die inserts 36, the pair of confronting broaching die members 30 is adapted to operate upon a pair of nail shanks simultaneously.

As stated, die members 30 are conjointly movable toward and away from the base plate (vertically in the positions illustrated in FIGS. 1 to 6) and are movable from an upper open position (FIGS. 3 and 4) downwardly to a closed broaching position, thence to a lowermost position. The movement of the broaching die members 30 is with respect to the base plate 12 and the support assembly of which base plate 12 is a part.

Die members 30 are oscillatably mounted on a pivot assembly 48. Pivot assembly 48 comprises a pivot rod 50 and a pivot member 52. The ends of pivot rod 50 project through vertically elongated slots 54 in stops l8. Retainers 56 hold pivot rod 50 against axial removal from slots 54. Pivot assembly 48 is movable vertically in slots 54.

Pivot rod 50 also projects through a reciprocable slide assembly 58. Slide assembly 58 comprises a pair of end plates 60 and a pair of side plates 62 which are connected to end plates 60 by a suitable plurality of screws 64. At their lower ends, side plates 62 are secured to a yoked bottom plate 66, as by a plurality of dowels 69 (see FIG. 6). The yoked portion of bottom plate 66 is proportioned to receive a drive link 70 and to be secured thereto by a link pin 72. When link 70 is moved it causes slide assembly 58 to reciprocate in the direction of movement of link pin 72.

Each of the side plates 62 defines a vertically elongated slot 76 through which the ends of pivot rod 50 project. As such, slide assembly 58 is adapted to move relative to the pivot rod 50 and also with respect to the slotted stops 18, hence toward and away from the base plate 12. The end plates 60 are proportioned to slide along slide blocks 24, thereby to guide the slide assembly on the support assembly during its reciprocable travel. Preferably the materials used to fabricate end plates 60 and slide blocks 24 are selected to minimize wear.

Pivot assembly 48 is disposed between the die members 30 and provides a common support upon which the die members may oscillate. Pivot member 52 is disposed in complementary confronting grooves 68 in the die members 30, so that the die members may oscillate about the axis of pivot member 52, as between a closed broaching position (FIG. 6) and an open nail shank receiving position (FIG. 4). Pivot member 52 is supported in spaced relation to the underlying bottom plate 66 by a compression spring 80. The ends of spring 80 are received in undercut seat areas in pivot member 52 and in bottom plate 66. Compression spring 80 normally thrusts pivot assembly 48 upwardly as far as it will go. Of course it also will thrust the die members 30 upwardly because pivot member 52 is received in the confronting grooves 68 therein. Depending upon the vertical position of slide assembly 58, compression spring 80 will thrust pivot rod 50 upwardly to the tops of slots 76 defined by side plates 62. In other words, the pivot rod 50 will always rest against the lowermost of the tops of slots 54 or slots 76 because of the presence of compression spring 80.

A further compression spring 82 is disposed between, and seated in confronting notches in die members 30 (FIGS. 4 and 5). Spring 82 acts to bias the upper ends of broaching die members 30 to the open position of FIG. 4 in which the die inserts 36 are spread apart to receive a nail shank. When they are biased to the open position, die members 30 oscillate about the axis of pivot member 52, and on bearing surfaces 83 which act against end plates 60 of slide assembly 58.

In the lower broaching positions, compression spring 82 is rendered inefiective to spread the die members 30. In those broaching positions a plurality of pivot links 84 act to hold the die members 30 in a closed position. Each of the pivot links 84 comprises a pair of cylindrical link segments, i.e., an inner link segment 86 and an outer link segment 88. Link segments 86 and 88 are disposed in, and oscillate with respect to the complementary grooves 90, 92 respectively, in end plates 60 and die blocks 32. Confronting surfaces of the pivot links 84 and of the end plates 60 and block 32 define flats 94, 94' so that the pivot links can oscillate relative to the grooves 90, 92 only away from and toward those flats. Therefore, for example, slide assembly 58 cannot move downwardly with respect to die members 30 beyond the position illustrated in FIG. 5, although the slide assembly may move upwardly with respect to the die members 30 from the position of FIG. 5. Because the distance between the axes of the cylindrical segments of each link always remains the same, when one such center is moved vertically with respect to the other, as from the position of FIG. 5 to the position of FIG. 4, compression spring 82 will be freed to bias the die blocks 32 outwardly to the position of FIG. 4 about the axis of pivot assembly 48. As such, the die members will oscillate with respect to the pivot assembly and with respect to the slide assembly, and will pivot (on links 84) with respect to the slide assembly.

Referring now to FIGS. 3 to 6, the movement of broaching die members 30 through a broaching cycle will be described. In FIG. 4, the die members 30 are in a full open position to receive the shanks of nail blanks. Drive link has been moved to its uppermost position, thereby carrying slide assembly 58 along the slide blocks 24 to its uppermost position relative to base plate 12 and relative to die members 30. At that time pivot rod 50 is positioned in its uppermost position at the top of slots 54 by compression spring 80, and side plates 62 have been elevated until the bottoms of the slots 76 are adjacent pivot rod 50. Also, side plates 62 have carried outer link segments 88 of links 84 upwardly with respect to inner link segments 86, allowing compression spring 82 to oscillate the die members 30 to the full open position of FIG. 4. In that position, the

shanks of nails can be moved transversely of their longitudinal axes between the die membcgs 30, as is illustrated in FIG. 4.

After the nail shanks have so positioned, link 70 is moved downwardly (through the position of FIG. 3), gradually returning the links 84 to a horizontal position (FIGS. 5 and 6).

The initial downward movement of link 70 simply closes the die members 30 by moving the slide assembly 58 downwardly with respect to the die members 30. After they have been moved to their closed position (FIG. 5), broaching surfaces 42 are in broaching contact with the shank above the distended portion D. At that time, the upper edges of slots 76 contact the pivot rod 50, and slide assembly 58 is then ready to carry the die members 30 downwardly through the position of FIG. 6 to breach the shank. Because the nails are held and restrained against axial downward movement as by a stop 100 (FIG. 2), the broaching surfaces 42 are carried downwardly against and along the nail shanks from above the distended portion of the shank, whereby the die inserts 36 act, as necessary, to straighten the shanks, to smooth the distended portions, and to reduce their diameters to preselected diameters. The range of downward movement of the die members 30 is limited, as by the lower edges of the slots 54 in stops 18.

As stated, a broaching device of this invention is adapted to operate on a pair of nails N having distended lower portions D (FIG. 7) simultaneously. Desirably, the nails are carried directly from a suitable pointing mechanism by a rotary nail carrier 102, each of the nails being carried in an individual support on the carrier 102. The die members 30 are proportioned to open wide enough so that the shanks of the nails may be moved between the die inserts transversely of their lengths, and generally at the elevation indicated in FIG. 2. After the nails are so positioned, nail carrier 102 stops, stops 100 engage the heads to support the nail against axial movement, and the broaching device 10 is cycled as has been described, returning finally to an open position. At that time, the broached nails are moved out of the broaching device, and a new pair of nails is moved in the broaching device for broaching, and a new broaching cycle is initiated.

It is intended that this invention shall not be limited to the specific embodiments illustrated and described since the foregoing description and drawings will suggest to those skilled in the art further modifications which are within the spirit and purview of this invention.

What is claimed is:

1. A method of making a nail having a head, an elongate shank and a pointed end in which a portion only of the elongate shank of the nail adjacent the pointed end has become distended in a pointing operation, the steps of supporting a plurality of nails on a nail carrier, carrying each of said nails from a pointing mechanism in a direction transversely of its length to a position in which the pointed end of said nail and the distended portion of said shank is disposed between spaced apart broaching surfaces, oscillatably moving said broaching surfaces towards each other and into broaching contact with said shank above the distended portion of said shank to a closed broaching position, then, while maintaining said broaching contact and while restraining said nail against axial movement, reciprocating said closed broaching surfaces axially of the shank portion from above said distended portion to the pointed end of said nail, thereby to reshape said distended portion, opening said broaching surfaces, and carrying said reshaped nail away in the same direction transversely of its len while simultaneously bringing another nail to a post ion between said spaced apart broaching surfaces.

2. An assembly for eliminating distension in the elongate shank of a pointed nail comprising means for supporting a nail against movement axially of its length, a support assembly including a base plate, a slide assembly supported for reciprocable movement with respect to said support assembly and with respect to said nail supporting means, a pair of broaching dies supported on said slide assembly for oscillatable movement with respect to said slide assembly when said slide assembly reciprocates, means for reciprocating said slide assembly with respect to said support assembly and for oscillatably moving said broaching dies with respect to said slide assembly between a first open nail shank receiving position and a second nail shank contacting position, for holding said broaching dies in said second position, and for moving said broaching dies longitudinally of the axis of a nail shank from above a distended position of a nail shank to the pointed end of the nail, thereby to eliminate the distension in a nail shank.

3. The assembly of claim 2 in which said broaching dies define broaching surfaces for contacting a said nail shank in said second position, and a common support on which said broaching dies oscillate, whereby said broaching dies are oscillatably movable with respect to each other about said common support and also with respect to said slide assembly. 

1. A method of making a nail having a head, an elongate shank and a pointed end in which a portion only of the elongate shank of the nail adjacent the pointed end has become distended in a pointing operation, the steps of supporting a plurality of nails on a nail carrier, carrying each of said nails from a pointing mechanism in a direction transversely of its length to a position in which the pointed end of said nail and the distended portion of said shank is disposed between spaced apart broaching surfaces, oscillatably moving said broaching surfaces towards each other and into broaching contact with said shank above the distended portion of said shank to a closed broaching position, then, while maintaining said broaching contact and while restraining said nail against axial movement, reciprocating said closed broaching surfaces axially of the shank portion from above said distended portion to the pointed end of said nail, thereby to reshape said distended portion, opening said broaching surfaces, and carrying said reshaped nail away in the same direction transversely of its length while simultaneously bringing another nail to a position between said spaced apart broaching surfaces.
 2. An assembly for eliminating distension in the elongate shank of a pointed nail comprising means for supporting a nail against movement axially of its length, a support assembly including a base plate, a slide assembly supported for reciprocable movement with respect to said support assembly and with respect to said nail supporting means, a pair of broaching dies supported on said slide assembly for oscillatable movement with respect to said slide assembly when said slide assembly reciprocates, means for reciprocating said slide assembly with respect to said support assembly and for oscillatably moving said broaching dies with respect to said slide assembly between a first open nail shank receiving position and a second nail shank contacting position, for holding said broaching dies in said second position, and for moving said broaching dies longitudinally of the axis of a nail shank from above a distended position of a nail shank to the pointed end of the nail, thereby to eliminate the distension in a nail shank.
 3. The assembly of claim 2 in which said broaching dies define broaching surfaces for contacting a said nail shank in said second position, and a common support on which said broaching dies oscillate, whereby said broaching dies are oscillatably movable with respect to each other about said common support and also with respect to said slide assembly. 